Insertion devices (ID's) also known as undulators and wigglers are used in second and third generation synchrotrons and linear particle accelerators such as free electron laser facilities. Insertion devices are designed to hold and precisely position arrays of strong magnets in proximity to the particle beam and thereby produce brilliant x-rays that are used for a broad range of scientific experiments. There are specific tolerance requirements for magnet array positioning for each insertion device, depending on parameters of the particular synchrotron or linear accelerator in which the device will be used, and also on parameters of the x-rays required for the particular scientific experiments planned using the x-ray light to be produced. Magnetic force levels contained in insertion devices can range into the hundreds of kilonewtons while magnet array positioning accuracy requirement tolerances can be as little as ±1 micrometer.
Insertion devices are produced in two basic types, usually defined as planar or polarizing. The planar devices employ magnet arrays in an arrangement spatially constrained by the insertion device in a manner that produces only vertical attractive magnetic forces between the magnet arrays, as the insertion device drives the horizontally oriented girders so as to vertically translate the magnet arrays in close proximity above and below the particle beam. Polarizing insertion devices are more complex devices capable of moving the magnet arrays longitudinally as well as vertically and they see additional forces including repulsive vertical, and also transverse and longitudinal forces.
Very mechanically stiff structures are used to meet these requirements. The historical trend is towards stronger magnetic forces due to improved magnet materials, longer magnet arrays, and smaller gaps used between magnet arrays, while the positioning accuracy tolerances for the magnet arrays have become tighter in the newest generation synchrotrons and even tighter in free electron lasers. These trends challenge the existing mechanical support and drive systems configurations for the insertion devices. There is a need to significantly reduce detrimental modes of magnet array misalignments that occur under magnetic loading in the currently known insertion devices support frames.